Following [1]} we start with the Kerr metric in the Boyer-Lindquist
coordinates,
\(ds^{2} & =\left( 1-\frac{2Mr}{\Sigma }\right) dt^{2}+2\frac{A}{\Sigma }\omega _{d}\sin ^{2}\theta dtd\varphi \nonumber \\& -\frac{\Sigma }{\Delta }dr^{2}-\Sigma d\theta ^{2}-\frac{A\sin ^{2}\theta }{\Sigma }d\varphi ^{2}~, \) 
